Battery Pack Communication Circuit for Noise Loop Suppression
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Solution Overview
Problem
Existing power tool systems experience signal integrity issues due to noise currents flowing in closed loops between battery packs and power tools, leading to inaccurate data communication.
Innovation Solution
Incorporating noise current limiting circuits in both the battery pack and connected equipment to restrict noise current flow in reverse directions, while allowing signal transmission, thereby maintaining signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a closed loop is formed between negative electrode terminal and communication terminal for data communication, then data communication function is enabled, but noise currents can flow in the closed loop causing signal integrity degradation
Solution Approach 1:
A diode is introduced as an intermediary component in the communication terminal circuit. The diode allows data signals to pass through in the forward direction while blocking noise currents in the reverse direction, thus protecting the communication interface without preventing data transmission functionality
Solution Approach 2:
The harmful noise current flow path is extracted and blocked from the closed loop by using the diode's reverse blocking characteristic. This separates the useful data signal transmission function from the harmful noise current circulation, allowing the communication function to operate without interference
2Reliability
If noise current limiting circuit is added to protect against noise, then signal integrity is improved, but device complexity increases
Solution Approach 1:
A simple diode, which is a low-cost and widely available component, is used to implement noise current limiting. The diode provides reliable protection against noise currents while maintaining minimal circuit complexity and low cost, making it an economically viable solution
Solution Approach 2:
The circuit utilizes the inherent electrical parameter characteristics of the diode (forward conduction and reverse blocking) to achieve noise current limiting without requiring complex control circuits or additional active components, thus maintaining simplicity while improving reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures accurate data communication between battery packs and connected equipment by limiting noise currents, preventing signal degradation and ensuring reliable data transfer.
Implementation Method 1
a first diode D11, an anode of which is electrically connected to a connection point 26a in the signal path 26, and a cathode of which is electrically connected to an input terminal 23a of the data input circuit 23
Data Source
AI summary
A battery-powered system includes a battery pack (10; 71; 81) connected to an electrical equipment (30; 50; 76; 86). The battery pack includes a first positive electrode terminal (11), a first negative electrode terminal (12), a first communication terminal (13), a first data input circuit (23), and a first limiting circuit (D11; D72; D82) that limits a flow of electric current in a direction from the first negative electrode terminal to the first communication terminal via the first data input circuit. The connected equipment includes a second positive electrode terminal (31; 51), a second negative electrode terminal (32; 52), a second communication terminal (33; 53), a second data input circuit (43; 63; 77; 87), and a second limiting circuit (D31; D51; D77; D87) that limits a flow of electric current in a direction from the second negative electrode terminal to the second communication terminal via the second data input circuit.